Optical lens of optical scanner

ABSTRACT

An optical scanner that may assemble the lens design for varying the focus and resolution, having a light source, a reflection compound mirror, a charge coupled device, a basic objective lens and a compound lens. The basic objective lens is designed by simulation software. According to the lens design theory, the compound lens is designed. By incorporating the basic objective lens and the compound lens, different resolutions such as 1200 dpi, 1600 dpi and 2400 dpi of the optical scanner are obtained without redesigning the lens device, the current specification of the optical scanner is also varied.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of, and claims the prioritybenefit of, U.S. application Ser. No. 09/921,949 filed on Aug. 3, 2001,U.S. Pat. No. 6,587,247.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates in general to an optical scanner, and moreparticularly, to an optical scanner that may assemble different lensdesigns for changing focus and resolution.

2. Description of the Related Art

The conventional optical scanner (referring to FIG. 1) comprises a lightsource 100, a reflection compound mirror 400, an object lens 500 and anoptical sensor, such as a charge coupled device (CCD) 600. Whilescanning, the light source 100 radiates on the document 200, an imagelight is obtained via reflection or transmission. The reflectioncompound mirror 400 is comprised of several reflection mirrors (401,402, 403) located along the optical path. Therefore, the image of thedocument 200 is incident to the reflection compound mirror 400. Beingreflected by the reflection compound mirror 400, the image istransmitted to the objective lens 500. The objective lens can receivethe image of the document 200 transmitted from the reflection compoundmirror 400, and display such image in the charge coupled device 600.

The conventional objective lens is designed by simulation softwareaccording to the requirements of resolution, total track (TT),magnification and modulation transfer function (MTF) provided by theclient. The factors of lens, material, curvature, number of lenses,size, and length of the objective lens are thus determined. The sampleis then fabricated, and the inspection of the sample and simulation areperformed. For example, the objective lens 502 of 600 dpi as shown inFIG. 2a is normally formed of three lenses. The objective lens 504 of1200 dpi as shown in FIG. 2b is normally formed of four lenses.

According to the above, the conventional design of the objective lenshas to meet the specification requirements including the resolution, thetotal track, the magnification and the modulation transfer function. Fordifferent specification requirements, a new objective lens has to bedesigned. Alternatively, the specification of the current opticalscanner has to be changed.

SUMMARY OF THE INVENTION

The invention provides an objective compound lens design that may changethe focus and resolution without a redesign. By appropriately designingthe basic objective lens and incorporating it with various compoundlenses, the required resolution and specification can be obtained.

The object compound lens structure may change the focus and resolutionof the optical scanner by switching the object lenses.

The objective compound lens can be used in an optical scanner thatcomprises at least a light source, a reflection compound mirror and anoptical sensor. A light source is used to radiate a document to obtainan image light. The objective compound lens is located along the opticalpath of the image light between the optical sensor and the reflectioncompound mirror. The object compound lens comprises a basic object lensand at least a compound lens. The compound lens can be adjacent to ordetached from the basic objective lens. Or alternatively, more than onecompound lens can be installed on a seat and disposed between the basicobjective lens and the reflection compound mirror. Via a driving device,the seat can be driven, and the compound lenses on the seat can beincorporated with the basic objective lens.

While connecting the compound lens with the basic objective lens, orincorporating the compound lens with the basic objective lens, thecompound lens is located along the optical path of the image lightbetween the basic objective lens and the reflection compound mirror. Theoptical scanner can thus have different resolutions. Withoutincorporating the compound lens, the image light can be projected to theoptical sensor via the basic objective lens only, so that only a basicresolution is obtained.

Both the foregoing general description and the following detaileddescription are exemplary and explanatory only and are not restrictiveof the invention, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a conventional optical scanner;

FIGS. 2a and 2b show the conventional objective lens design;

FIG. 3 shows the basic objective lens design of the invention;

FIGS. 4a to 4d show the compound lenses designed for differentresolutions (4a, 4d for 1200 dpi, 4b for 1600 dpi and 4c for 2400 dpi);

FIGS. 5a to 5d show the basic objective lens assembled with variouscompound lenses;

FIG. 6 shows a first embodiment of the invention;

FIG. 7a shows a second embodiment of the invention;

FIG. 7b shows a fixed seat used in the second embodiment;

FIG. 8a shows a third embodiment of the invention;

FIG. 8b sows the linear seat used in the third embodiment of theinvention; and

FIG. 8c shows the disk-like seat used in the third embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

First Embodiment

FIG. 6 shows a first embodiment of an optical scanner according to theinvention. This embodiment belongs to a contact assembling type. Theoptical scanner comprises a light source 100, a reflection compoundmirror 400, an optical sensor such as a charge coupled device 100, abasic objective lens 510 and a compound lens (522 in this embodiment).In FIG. 3, the basic objective lens 510 is designed by simulationsoftware according to various resolutions such as 600 dpi, 1200 dpi,1600 dpi and 2400 dpi. The compound lens is selected from the compoundlenses 520 to meet the required resolution, for example, the compoundlens 522 can be selected. As shown in FIGS. 4a, 4b, 4c and 4d, thecompound lenses 522 and 528 are selected to meet the resolution 1200dpi, the compound lens 524 is selected to meet the resolution 1600 dpi,and the compound lens 526 is selected for the resolution 2400 dpi. Afterassembling the basic compound lens 510 and the compound lens, anobjective compound lens that meets the resolution requirement isobtained, as shown in FIGS. 5a (1200 dpi), 5b (1600 dpi), 5c (2400 dpi)and 5d (1200 dpi). In FIG. 3, the compound lens is detachable from thebasic objective lens. Via the screw thread (linkage apparatus) inside oroutside of the basic objective lens, the compound lens can be connectedwith the basic object lens. It is appreciated that the skilled personmay apply other mechanisms to connect these two lenses. With differentresolution requirements, compound lenses with different resolutions canbe changed without redesigning the whole objective compound lens. Inaddition, the additionally applied compound lens is located at theoptical path of the image light 100 between the basic objective lens 510and the reflection compound mirror 400. The basic objective lens 510 canalso be used independently to result in a basic resolution (600 dpi) ofthe image light 110 projected to the optical sensor 600.

Second Embodiment

In FIG. 7a, a second embodiment of an optical scanner is illustrated.The embodiment is a non-contact assembling type. The optical scannercomprises a light source 100, a reflection compound mirror 400, anoptical sensor such as a charge coupled device 600, a basic objectivelens 510, a compound lens (522 in this embodiment) and a mounting seat700. The basic objective lens 510 is designed by simulation software tomeet the resolution requirement (such as 600 dpi) and other resolutionrequirements such as 1200 dpi, 1600 dpi and 2400 dpi. The compound lensis selected from the compound lenses 520 to meet the specific resolutionrequirement. For example, the compound lens 522 is selected. Thecompound lens 522 is mounted on the mounting seat 700 as shown in FIG.7b. Each objective lens is incorporated to meet different resolutionrequirements. By incorporating the basic objective lens with differentcompound lenses, various resolution requirements can be met withoutredesigning the whole objective compound lens.

In FIG. 8a, a third embodiment of an optical scanner is illustrated. Theembodiment is a non-contact assembling type. The optical scannercomprises a light source 100, a reflection compound mirror 400, anoptical sensor such as a charge coupled device 600, a basic objectivelens 510, a compound lens 520, a seat 800, a gearing and a driver. Thebasic objective lens 510 is designed by simulation software to meet theresolution requirement (such as 600 dpi) and other resolutionrequirements such as 1200 dpi, 1600 dpi and 2400 dpi. Various compoundlenses 522, 524 and 526 are included in the compound lenses 520 to meetdifferent resolution requirements (1200 dpi, 1600 dpi, 2400 dpi). Thecompound lenses 522, 524 and 526 are arranged and mounted on a gearstrip 801 of the seat 800 as shown in FIG. 8b. The gear strip 801 isdriven by the gearing to shift linearly. To switch between differentresolutions, a motor 1000 drives the gearing 900 according to a firmwarecommand to drive the compound lens 520 on the seat, until the compoundlens meeting the resolution requirement is selected. In FIG. 8c, theseat 800 that switches the compound lens linearly is replaced with arotation disk 1100. The compound lenses 522, 524 and 526 are evenlydistributed on the perimeter of the disk 1100 with the same distance tothe center of the disk 1100. While switching between differentresolutions, firmware can be used to command the motor 100 to drive thegearing 900 to rotate the seat 1100, so that the compound lens thatmeets the resolution requirement is selected. By incorporating theobjective lens with the compound lens, various objective compound lensesto meet different resolution requirements are obtained. The gearing isselected from a group consisting of gear strips, gear, lead screw, steeltape, belt and a combination of the above.

Accordingly, the invention comprises at least the following advantages:

-   -   (1) The objective lens design of the scanner is modularized.        According to different resolutions, magnifications, optical        lengths and image quality requirements, a compound lens is        incorporated without redesigning the objective lens or changing        the current scanner design. The reuse rate of the scanner is        also increased.    -   (2) In the objective lens design provided by the invention, the        basic objective lens has a constant form, so that it can be        reused for different resolution requirements. The design cost is        reduced, and the redefine and lens simulation required by        changing lens design are also avoided.    -   (3) The compound lens in the first and second embodiment can be        adjusted by the user without effecting a major adjustment of the        system. In the third embodiment, the compound lens is        automatically changed according to the resolution required by        user. The optical scanner is upgraded for having different        optical resolutions.    -   (4) The design of the compound lens can be switched for various        resolutions so that the design cost of the objective lens is        decreased.    -   (5) The compound lens can be adjusted according to the image        requirement of the customers.

Other embodiments of the invention will appear to those skilled in theart from consideration of the specification and practice of theinvention disclosed herein. It is intended that the specification andexamples to be considered as exemplary only, with a true scope andspirit of the invention being indicated by the following claims.

1. An objective compound lens, applied to an optical scanner having atleast a light source, a reflection compound mirror and an opticalsensor, wherein the light source is used to radiate illuminate adocument to obtain an image light, the reflection compound mirror islocated in an optical path of the image light to protect the image lighton the optical sensor, and the objective compound lens is locatedbetween on the optical path of the image light between the opticalsensor and the reflection compound mirror, the objective compound lenscomprising: a basic objective lens; and a mounting seat; and a pluralityof compound lenses, only one of which is suited for connecting anddetaching with the mounting seat,a mounting seat configured toreleasably couple a compound lens thereto, the mounting seat configuredto support and fix the compound lens in alignment with the basicobjective lens when the compound lens is releasably coupled thereto,wherein when only one of the compound lenseslens is selected to beallocated onreleasably coupled to the mounting seat, the optical scannerhas a resolution corresponding to the selectedreleasably coupledcompound lens, and when any one of the compound lenseslens is notconnectedcoupled to the mounting seat, the image light is projected onthe optical sensor via the basic objectobjective lens only.
 2. Theoptical objective compound lens according to claim 1, wherein when theselected compound lens is coupled to the mounting seat, the compoundlens is located on the optical path of the image light between the basicobjective lens and the reflection compound mirror.
 3. The opticalobjective compound lens according to claim 1, wherein when the selectedcompound lens is coupled to the mounting seat, the compound lens isallocated on the mounting seat, separating from non-contacting with thebasic objective lens.
 4. An optical scanner, comprising: a basicobjective lens positioned to receive light and to project the receivedlight onto an optical sensor; and a mounting seat configured toreleasably couple a compound lens thereto, the mounting seat configuredto support and fix the compound lens in alignment with the basicobjective lens when the compound lens is releasably coupled thereto,wherein when the compound lens is releasably coupled to the mountingseat the light passes through both the basic objective lens and thecompound lens before being projected onto the optical sensor, and whenthe compound lens is not coupled to the mounting seat the light does notpass through the compound lens before being projected onto the opticalsensor.
 5. The optical scanner of claim 4, wherein the optical scanneris configured to scan objects according to a first resolution range whenthe compound lens is releasably coupled to the mounting seat, and theoptical scanner is configured to scan the objects according to a secondresolution range when the compound lens is not coupled to the mountingseat, wherein the second resolution range is different than the firstresolution range.
 6. The optical scanner of claim 4, wherein when thecompound lens is releasably coupled to the mounting seat, the compoundlens is non-contacting with the basic objective lens.
 7. The opticalscanner of claim 4, wherein when the compound lens is releasably coupledto the mounting seat, a distance between the compound lens and the basicobjective lens is fixed.
 8. The optical scanner of claim 4, wherein whenthe compound lens is releasably coupled to the mounting seat, a positionof the compound lens is fixed and non-moving relative to the basicobjective lens.
 9. An optical scanner, comprising: means for focusinglight to be projected onto an optical sensor; and means for mounting acompound light focusing component in alignment with the light focusingmeans, wherein the means for mounting is configured to releasably affixthe compound light focusing component thereto, such that the mountedcompound light focusing component is readily interchangeable with othercompound light focusing components; wherein the means for mounting ispositioned in the optical scanner, such that when the compound lightfocusing component is releasably affixed to the means for mounting thelight is focused by both the means for light focusing and the compoundlight focusing component before being projected onto the optical sensor,and when the compound light focusing component is not affixed to themeans for mounting, the light is focused by the means for light focusingand not the compound light focusing component.
 10. The optical scannerof claim 9, wherein the optical scanner is configured to scan objectsaccording to a first resolution range when the compound light focusingcomponent is releasably affixed to the means for mounting, and theoptical scanner is configured to scan the objects according to a seconddifferent resolution range when the compound light focusing component isnot affixed to the means for mounting.
 11. The optical scanner of claim10, wherein the optical scanner is configured to scan the objectsaccording to a third resolution range when another compound lightfocusing component is releasably affixed to the means for mounting.